微信小程序之蓝牙开发遇到的坑
程序员文章站
2022-01-13 10:59:40
微信小程序之蓝牙开发流程图[外链图片转存失败,源站可能有防盗链机制,建议将图片保存下来直接上传(img-3qeF44jR-1596178058338)(https://imgkr2.cn-bj.ufileos.com/0ff96f66-0dff-4cb0-b42d-b4b0cf18db2a.png?UCloudPublicKey=TOKEN_8d8b72be-579a-4e83-bfd0-5f6ce1546f13&Signature=YsCNtt4qZ1oniawMhNElsJg3VP0%253...
微信小程序之蓝牙开发遇到的坑
遇到的坑
-
低版本手机未打开系统定位服务时,可能出现搜索不到蓝牙设备,所以最好在页面中提示用户打开定位服务。
-
微信需授权蓝牙,在手机设置里面打开,否则使用不了蓝牙。
-
部分api需延时调用否则安卓手机有问题(startBluetoothDevicesDiscovery,getBluetoothDevices,writeBLECharacteristicValue)
-
连接蓝牙,实际上可能已经连接上,但是小程序api调用会返回10003连接失败,安卓手机会出现
-
断开蓝牙,小程序api调用会返回调用成功,实际上并可能没有与设备断开,安卓手机会出现
流程图
使用
1.初始化蓝牙模块
onLoad: function () {
let that = this
that.loadDate();
},
loadDate() {
let that = this;
//初始化蓝牙模块
wx.openBluetoothAdapter({
success: (res) => {
//获取本机蓝牙适配器状态。
that.getBluetoothAdapterState()
},
fail: (res) => {
if (res.errCode === 10001) {
//手机蓝牙未打开,弹出提示框让用户打开
that.setData({
bluetoothON: false
})
//监听蓝牙适配器状态变化
wx.onBluetoothAdapterStateChange(function (res) {
if (res.available) {
that.setData({
bluetoothON: true
})
//获取本机蓝牙适配器状态。
that.getBluetoothAdapterState()
}
})
}
}
})
},
2.获取本机蓝牙适配器状态
//获取本机蓝牙适配器状态。
getBluetoothAdapterState() {
var that = this;
wx.getBluetoothAdapterState({
success: function (res) {
that.setData({
bluetoothON: true
})
that.startBluetoothDevicesDiscovery()
},
fail(res) {
console.log(res)
}
})
},
3.搜寻附近的蓝牙外围设备
//开始搜寻附近的蓝牙外围设备。此操作比较耗费系统资源,请在搜索并连接到设备后调用 wx.stopBluetoothDevicesDiscovery 方法停止搜索。
startBluetoothDevicesDiscovery() {
var that = this;
setTimeout(() => {
wx.startBluetoothDevicesDiscovery({
success: function (res) {
/* 获取蓝牙设备列表 */
that.getBluetoothDevices()
},
fail(res) {
console.log(res)
}
})
}, 1000)
},
4.获取搜索到的蓝牙设备列表
// //获取搜索到的蓝牙设备列表
getBluetoothDevices() {
var that = this;
setTimeout(() => {
wx.getBluetoothDevices({
success: function (res) {
if (res.devices.length > 0) {
//可使用设备
let searchDevices = res.devices.filter(item => item.localName && item.localName.startsWith("EFF"));
//这里根据业务需求找出你想连接的设备,调用connect2Bluetooth
that.connect2Bluetooth(deviceId)
} else {
//没有搜索到设备
console.log("没有搜索到设备")
}
},
fail(res) {
console.log(res)
}
})
}, 2000)
},
5.连接蓝牙
//连接蓝牙
connect2Bluetooth(deviceId) {
let that = this;
wx.createBLEConnection({
deviceId: deviceId,
success: function (res) {
that.setData({
connected: true,
})
//设置蓝牙最大传输单元。需在 wx.createBLEConnection调用成功后调用,mtu 设置范围 (22,512)。安卓5.1以上有效。安卓手机在数据接收限制在20个字节内。苹果手机好像没有限制,可以调用此方法改变大小
wx.setBLEMTU({
deviceId: that.data.deviceId,
mtu: 247,
success: (res) => {
console.log("setBLEMTU success>>", res)
},
fail: (res) => {
console.log("setBLEMTU fail>>", res)
}
})
/*获取连接设备的service服务 */
that.getBLEDeviceServices();
//停止搜索设备
wx.stopBluetoothDevicesDiscovery()
//监听蓝牙连接状态
wx.onBLEConnectionStateChange(function (res) {
that.setData({
connected: res.connected
})
app.globalData.connected = res.connected
if (!res.connected) {
console.log("*******************蓝牙连接已断开*****************")
}
})
},
fail: function (res) {
console.log(res)
log.warn(res)
}
})
},
- 获取蓝牙设备的service服务,获取的serviceId有多个要试着连接最终确定哪个是稳定版本的service 获取服务完后获取设备特征值
getBLEDeviceServices() {
let that = this;
wx.getBLEDeviceServices({
deviceId: that.data.deviceId,
success: function (res) {
/* 获取连接设备的所有特征值 */
for (let i = 0; i < res.services.length; i++) {
//看你自己项目需求
if (res.services[i].uuid.toUpperCase().indexOf("FFF0") != -1) {
//获取设备特征值
that.getBLEDeviceCharacteristics(res.services[i])
}
}
},
fail: (res) => {
console.log(res)
}
})
},
7.获取蓝牙设备特征值
getBLEDeviceCharacteristics(services) {
let that = this;
wx.getBLEDeviceCharacteristics({
deviceId: that.data.deviceId,//// 这里的 deviceId 需要已经通过 createBLEConnection 与对应设备建立链接
serviceId: services.uuid,// 这里的 serviceId 需要在 getBLEDeviceServices 接口中获取
success: function (res) {
for (var i = 0; i < res.characteristics.length; i++) {
let item = res.characteristics[i]
if (item.properties.read && item.properties.write && (item.properties.notify || item.properties.indicate)) {
/* 获取蓝牙特征值 */
wx.readBLECharacteristicValue({
deviceId: that.data.deviceId,
serviceId: services.uuid,
characteristicId: item.uuid,
})
app.globalData.deviceId = that.data.deviceId;
app.globalData.serviceId = services.uuid;
app.globalData.characteristicId = item.uuid;
//写数据
// 启用低功耗蓝牙设备特征值变化时的 notify 功能
that.notifyBLECharacteristicValueChange(that.data.deviceId, services.uuid, res.characteristics[i].uuid)
}
}
},
fail: function (res) {
console.log(res)
}
})
},
8.启动notify 蓝牙监听功能
notifyBLECharacteristicValueChange(deviceId, serviceId, characteristicId) { // 启用低功耗蓝牙设备特征值变化时的 notify 功能
var that = this;
wx.notifyBLECharacteristicValueChange({
state: true,
deviceId: deviceId,
serviceId: serviceId,
characteristicId: characteristicId,
type: 'notification',//安卓手机需要加这个
complete(res) {
console.log(res, '启用低功耗蓝牙设备监听成功')
//监听获取数据
wx.onBLECharacteristicValueChange((characteristic) => {
//设备返回的数据转16进制
let recBuffer = blueTooth.ab2hex(characteristic.value);
})
},
fail(res) {
console.log(res, '启用低功耗蓝牙设备监听失败')
}
})
},
工具类 blueTooth.js
//ArrayBuffer转16进制数组示例
function ab2hex(buffer) {
// let byteRecBuffer =[];
var hexArr = Array.prototype.map.call(
new Uint8Array(buffer),
function (bit) {
return ('00' + bit.toString(16)).slice(-2)
}
)
return hexArr;
}
//往蓝牙写数据
function writeBLECharacteristicValue(str) {
console.log('写入:' + str)
let dataBuffer = new ArrayBuffer(str.length)
let dataView = new DataView(dataBuffer)
for (var i = 0; i < str.length; i++) {
dataView.setUint8(i, str[i])
}
wx.writeBLECharacteristicValue({
deviceId: getApp().globalData.deviceId,
serviceId: getApp().globalData.serviceId,
characteristicId: getApp().globalData.characteristicId,
value: dataBuffer,
success: function (res) {
console.log("写入成功")
},
fail: function (res) {
console.log('写入失败' + res.errMsg)
},
})
}
// 断开设备连接
function closeConnect() {
if (getApp().globalData.deviceId) {
wx.closeBLEConnection({
deviceId: getApp().globalData.deviceId,
success: function(res) {
console.log("蓝牙断开连接")
closeBluetoothAdapter()
},
fail(res) {
}
})
} else {
closeBluetoothAdapter()
}
}
// 关闭蓝牙模块
function closeBluetoothAdapter() {
wx.closeBluetoothAdapter({
success: function(res) {
console.log("关闭蓝牙模块")
},
fail: function(err) {
}
})
}
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本文地址:https://blog.csdn.net/qq_43643538/article/details/107713496